"Therefore . . ." - Crossword Clue, Answer and Explanation

'therefore' is the definition.
(I know that therefore can be written as thus)

This is all the clue.

(Other definitions for thus that I've seen before include "In this way" , "as indicated" , "an original Christmas gift" , "It follows" , "Therefore, hence" .)

I've seen this clue in The Mirror, The New York Times, The Independent, the Sydney Morning Herald, The Wall Street Journal, the Universal, The Sun, the Penny Press, the Newsday, the Evening Standard, the LA Times, The Washington Post, The Star Tribune, The Telegraph, The Guardian, the USA Today, The Times, the Newsday.com and the King Feature Syndicate.

'therefore' is the definition.
(I've seen this before)

This is all the clue.

(Other definitions for ergo that I've seen before include "Thus" , "Consequently" , "'Cogito, ---- sum'" , "so philosopher wrote in Latin" , "It follows" .)

I've seen this clue in The Mirror, The New York Times, The Independent, the Sydney Morning Herald, The Wall Street Journal, the Universal, The Sun, the Penny Press, the Newsday, the Evening Standard, the LA Times, The Washington Post, The Star Tribune, The Telegraph, The Guardian, the USA Today, The Times, the Newsday.com and the King Feature Syndicate.

'therefore' is the definition.
('so' can mean 'consequently' or 'therefore')

This is the entire clue.

I've seen this clue in the King Feature Syndicate.

"Therefore . . ." (5)